Search results for "plant disease"

Exopolysaccharides favor the survival of Erwinia amylovora under copper stress through different strategies.

2010

Erwinia amylovora causes fire blight, a destructive disease of rosaceous plants very difficult to control. We demonstrated that copper, employed to control plant diseases, induces the "viable-but-nonculturable" (VBNC) state in E. amylovora. Moreover, it was previously reported that copper increases production of its main exopolysaccharide (EPS), amylovoran. In this work, the copper-complexing ability of amylovoran and levan, other major EPS of E. amylovora, was demonstrated. Following this, EPS-deficient mutants were used to determine the role of these EPSs in survival of this bacterium in AB mineral medium with copper, compared to their wild type strain and AB without copper. Tot…

STUDY ON CONVERSION OF ENCAPSULATED VITRO-DERIVED PROPAGULES OF 'C35' CITRANGE [C. SINENSIS (L.) OSB. × P. TRIFOLIATE (L.) RAF.]

2015

Fight against Citrus tristeza virus (CTV) implies the use of CTV-resistant rootstocks, such as citranges [C. Sinensis (L.) Osb. × P. Trifoliata (L.) Raf.]. The 'C35' represents a promising tolerant to CTV genotype. The employment of innovative in vitro techniques, such as encapsulation, could open new perspectives for this genotype propagation, particularly in the nursery activity. Preliminary experiments on calcium-alginate encapsulation of microcuttings (unipolar propagules) have already been performed to evaluate the use of tissue culture for the propagation and the preservation of different citrange rootstocks: Carrizo and Troyer. In the present study, the influence of different types a…

Presence of endophytic bacteria in Vitis vinifera leaves as detected by Fluorescence in situ hybridization

2010

Fluorescence in situ hybridization (FISH) in combination with confocal laser scanning microscopy (CLSM) was applied to detect and localize bacterial colonies in leaf tissues of Vitis vinifera. Leaves were cleared to minimize the autofluorescence of plant fragments. The use of fluorescently labeled bacterial probe EUB338 on discolored grapevine leaf disks allowed the estimation of the spatial distribution of different bacterial colonies. In particular, bacterial colonies were found in veins, cells, hairs, intercellular spaces, and in cut edges of leaf disks of both non-Acremonium byssoides-colonized and A. byssoides-colonized leaves of five different cultivars. Furthermore, CLSM confirmed th…

Role of dioxygenase α-DOX2 and SA in basal response and in hexanoic acid-induced resistance of tomato (Solanum lycopersicum) plants against Botrytis …

2015

Resistance of tomato (Solanum Lycopersicum) to the fungal pathogen Botrytis cinerea requires complex interplay between hormonal signalling. In this study, we explored the involvement of new oxylipins in the tomato basal and induced response to this necrotroph through the functional analysis of the tomato α-dioxygenase2 (α-DOX2)-deficient mutant divaricata. We also investigated the role of SA in the defence response against this necrotrophic fungus using SA-deficient tomato nahG plants. The plants lacking dioxigenase α-DOX2, which catalyses oxylipins production from fatty acids, were more susceptible to Botrytis, and hexanoic acid-induced resistance (Hx-IR) was impaired; hence α-DOX2 is requ…

Characterisation of Pythium paroecandrum and its antagonism towards Botrytis cinerea, the causative agent of grey mould disease of grape.

2004

Pythium paroecandrum (B-30), an oomycete, was isolated from soil samples taken from a wheat field in Genlis in the Burgundy region of France and was found to check the growth and development of Botrytis cinerea, a serious grapevine pathogen. The oomycete is a fast-growing organism, living on vegetable debris, and can be recognised by its catenulate hyphal swellings, catenulate oogonia, and monoclinous antheridia. When grown together with B. cinerea, the causal agent of the grey mould disease of the grapevine, P. paroecandrum shows a pronounced antagonism and suppresses its growth and its aptitude to provoke the grey mould symptoms. Morphological features of this oomycete, its antagonism to …

A new mycoparasite, Pythium lycopersicum, isolated in Isparta, Turkey: morphology, molecular characteristics, and its antagonism with phytopathogenic…

2008

Pythium lycopersicum sp. nov. has been isolated from soil samples taken in an agricultural land in the Isparta region of Southern Turkey. This oomycete is characterized by its contiguous sporangia having globose to elongated elements linked with hyphal filaments, ornamented oogonia, and monoclinous antheridia with large antheridial cells. The oomycete is reminiscent of Pythium ornamentatum described by the corresponding author in 1987 from soil samples taken in Algeria. Sequence analyses of the internal transcribed spacer (ITS) regions of rRNA show a close relationship with Pythium oligandrum and other mycoparasites possessing ornamented oogonia. Morphological and molecular features of this…

Absence of the endo-beta-1,4-glucanases Cel1 and Cel2 reduces susceptibility to Botrytis cinerea in tomato.

2007

Cel1 and Cel2 are members of the tomato (Solanum lycopersicum Mill) endo-beta-1,4-glucanase (EGase) family that may play a role in fruit ripening and organ abscission. This work demonstrates that Cel1 protein is present in other vegetative tissues and accumulates during leaf development. We recently reported the downregulation of both the Cel1 mRNA and protein upon fungal infection, suggesting the involvement of EGases in plant-pathogen interactions. This hypothesis was confirmed by assessing the resistance to Botrytis cinerea infection of transgenic plants expressing both genes in an antisense orientation (Anti-Cel1, Anti-Cel2 and Anti-Cel1-Cel2). The Anti-Cel1-Cel2 plants showed enhanced …

Metabarcoding Analysis of Fungal Diversity in the Phyllosphere and Carposphere of Olive (Olea europaea)

2015

The fungal diversity associated with leaves, flowers and fruits of olive (Olea europaea) was investigated in different phenological stages (May, June, October and December) using an implemented metabarcoding approach. It consisted of the 454 pyrosequencing of the fungal ITS2 region and the subsequent phylogenetic analysis of relevant genera along with validated reference sequences. Most sequences were identified up to the species level or were associated with a restricted number of related taxa enabling supported speculations regarding their biological role. Analyses revealed a rich fungal community with 195 different OTUs. Ascomycota was the dominating phyla representing 93.6% of the total…

Viruses of Cetaceans

2011

Diagnostic accuracy of clinical parameters to monitor peri-implant conditions: A matched case-control study

2018

International audience; Background: The aim of this case-control study was to estimate the diagnostic accuracy of the standard clinical parameters in diagnosing healthy peri-implant tissues, peri-implant mucositis, and peri-implantitis.Methods: A case-control study was designed to compare the clinical parameters used in the diagnosis of peri-implant diseases such as: probingdepth (PD), bleeding on probing (BOP), mucosal redness (MR), suppuration (SUP), and plaque index (PI). Furthermore, the influence of patient-(sex, age) and implant-related variables (implant neck configuration, time in function after loading) were evaluated to investigate the association with the clinical findings. The i…